Organizers of the demonstration say they will hold a "general assembly" at 3 p.m, which they describe as an opportunity to recruit new supporters and share ideas.
"The Washington Square Park thing is a great way to bring us to the next level," said Michael Fix, an organizer of the demonstration.
There are no plans at this stage to set up a 24-hour camp in Washington Square Park similar to the one that has operated for three weeks in Lower Manhattan's Zuccotti Park.
The protesters living in Zuccotti Park have built a full-service demonstration staging zone, complete with hot food, health care, a digital counter registering supporters, and a solar energy truck to help supply power to electronics.
First-year medical resident Jay Kang arrived Friday to serve as a health care volunteer.
"The greed that is prevailing on Wall Street is causing a lot of problems in society today," Kang said.
"That is why I am here to support the protesters."
Occupy Wall Street set up in Zuccotti Park last month with dozens of demonstrators. Since then, thousands more -- including various unions such as the Transport Workers Union and the United Federation of Teachers -- have joined the movement.